A device for an electric switch formed as a low-voltage circuit-breaker is known from German Patent Specification 195 03 624 C1. In the case of this known device, one end of a push element formed as a push rod is supported under spring force on the door by way of a pressure piece fastened to the door of the switchgear cell. In this case, the push rod is arranged in a guiding tube, which is provided with a slit front part.
The pressure piece engages in this slit front part. When the door is closed, the other end of the push rod rests on the lower end of the oblique surface, inclined in the direction of the travelling path of the switch, in such a way that it assumes a relatively lowered position with respect to a sensing angle of the blocking mechanism and the blocking mechanism is consequently in a release position.
In this release position, the travelling mechanism of the switch is released for actuation. During opening of the door, the pressure piece leaves the slit front part of the guiding tube. The push rod follows this movement under the influence of the spring force until the other end of the push rod reaches the upper end of the oblique surface, and consequently achieves a relatively raised position. In this case, the sensing angle is pivoted, and the blocking mechanism is thereby transferred into its blocking position. In this blocking position, the travelling mechanism of the switch is blocked to prevent actuation.